Etching apparatus



July 1, 1924. 1,499,879

C. O. SCHMITT ET AL ETCHING APPARATUS Filed May 26. 1923 Jnvenfoz CHARLES 0. so

To all whom it may concern:

ai nown that We QHA PES SOHMITT d. Warren ."L EHLEEBGJ. citizens of the United States, residing at Sioux Falls, in the county of Minnehaha and State of South Dakota, have invented certain new and useful Improvements in Etching Apparatus, of which the following is a specification.

This invention relates to certain new and useful improvements in etching apparatus and the primary object thereof is to provide an apparatus which projects a uniform spray of the etching fluid against the surface of the metal to be etched, the latter being disposed at the top of the tank or vat containing the etching fluid.

A further object of the invention is to provide projecting means which includes dippers which are formed so as to eliminate back-lash or vacuum beneath the dippers as the latter pass through the etching fluid.

A still further object of the invention is to provide an apparatus of this type which can be efficiently operated with a minimum of etching fluid.

Still further and other objects will be later set forth and manifested in the course of the following description.

In the drawings Figure 1, is a central transverse sectional view of the invention on line. 11 of Figure 2;

Figure 2, is a section on line 22 of Fig-' ure 1, on a reduced scale;

1 Figure 3, is an enlarged front elevation of one of the dippers, and

Figure 4, is a side elevation of Figure 3, partly broken away and in section.

In proceeding in accordance with the present invention, a tank or vat 1 is employed, the bottom 2 of which is of concave form and is provided with a drain 3 at one end a head 9. The heads have flared open mouths 10, and closed rear ends 11, the pe ripheral portions 13 of the heads being of curved or arouate form. The rear ends of the heads are of converging or tapering form, while the peripheral portions or walls niur'rr nun WALTER n. nnnni'snno;

*nronrivenrraaarns. r

si -WXP The eter ;j g-pana al minum, each hub having a pair located at diametrically opposite points thereon.

By referring to Figure 4 of the drawings, it will be seen that the circumference of each dipper from point A, to point B is so designed that the distance from A to C, the lat-' ter the center of the hub, is greater than the distance from B to C, which eliminates the formation of vacuum under the dippers as the latter pass through the etching fluid.

The metal plate P to be etched is supported at the top of the tank as shown in Figure 1.

In operation, referring to Figure 1, it will be seen that by virtue of the concave bottom 2, a sufficient depth of fluid will be afforded with use of but a comparatively small quan tity. The mouths of the dippers dip into the fluid but to a slight extent beneath the surface of the latter, and due to the rearward convergence of the dippersvtowardsthe heels thereof, the fluid caught in the dipper is forced toward the outlets 14 and projected through the latter and against the plate being etched. The dippers are arranged in staggered relation as shown in Figures 1 and 2 so as to maintain a constant and uniform spray against the plate P.

What is claimed is 1. In an etching apparatus, a tank having a concave bottom, a shaft extending lengthwise of the tank, and a series of dippers arranged'in' pairs and carried by the shaft, each pair of dippers having a hub and spokes connecting the dippers to the hub, each, dipper having a flared mouth, a tapered closed rear end and a curved peripheral wall formed with a series of outlets disposed adjacent to the apex of the tapered rear end, the distance from the center of the hub to the front of the mouth being greater than the distance from the center of the hub'to the apex of the tapered rear end.

2. In an etching apparatus, a tank, ashaft therein, and a dipper carried by the shaft, the dipper having a mouth and a closed rear end and outlets adjacent to the latter, the distance from the center of the shaft to the mouth being greater than the distance from the center of the shaft to the closed rear end to prevent the formation of vacuum beneathold do. PM.

ti sitters 4. n1 etching apparatus, a tank, a shaft therein, and a dipper on the shaft having a flared mouth and a converging rear portion, the axis ofthe mouth being arranged at an angle to the axis of the rear portion, the rear portion being formed with fluid discharge openings.

In testimony whereof We afiix our signa- 20 tures.

CHARLES, o. :soHM-rrr'. WALTER F. FEHLBERG, 

